During the Ottoman Empire, İçil was a sanjak (an administrative unit smaller than vilayet and larger than kaza) in south Turkey.
Although it borders the Mediterranean Sea, the Toros Mountains, which are mostly impassable (except for the Sertavul Pass), may be the reason of the name, was first documented in the 12th century by Sejukid Turks.
According to salname (annual) of Adana Vilayet, there were six kazas (districts, now called ilçe) in the sanjak; namely, Anamur, Ermenek, Gülnar, Karataş, Mut, and Silifke.
Except for Gazipaşa and Ermenek İçil was the west part of the current Mersin Province.
In the early years of the Republic, İçel was an il (province) and its capital was Silifke.